Chemical cleaning compounds have long been advantageously used in a variety of contexts. Such compounds are produced in solid, granulated or powdered, and liquid forms. Typically, a cleaning compound is mixed with a solvent (e.g., water) to form a cleaning solution. Preferred embodiments of the present invention include methods and apparatus for dispensing cleaning solutions to a "utilization point," e.g., a dishwashing or laundry washing machine. Since one very common utilization point is a laundry machine, the present invention will be described in this context. It should be emphasized that the present invention is not limited to laundry washing applications, however.
In most commercial laundry machines it is desirable to dispense more than one type of solution to the washing zone. For example, detergent, fabric softener, souring agent and bleach are often utilized. These products are typically entirely incompatible: the detergent is alkaline, the souring agent is acidic, and the bleach is, for example, sodium hypochlorite (NaOCl) or the like. If the acidic souring agent comes into contact with the bleach, toxic chlorine gas can form. Also, if the alkaline detergent encounters the acidic sour, or vice versa, neutralization and loss of the desired effect will occur to some degree. Thus, laundry machines have historically possessed cleaning solution dispensers having an independent delivery system (e.g., separate conduit and pump) for each incompatible solution. While this technique is generally useful for its intended purpose, it is also unnecessarily expensive since each independent delivery system requires its own pump, its own delivery conduit, and so on. The capital cost of such a system becomes particularly high when sensors (e.g., conductivity and/or temperature sensors) are used in each individual delivery system. Not only are such systems unnecessarily expensive, they can be unsightly, space-consuming and possess a greater risk of failure (because of the larger number of fittings and components). The present invention is directed toward methods and apparatus for delivering multiple, possibly incompatible, products using a single delivery system.
Continuing with the laundry washing example, commercial laundries often have several laundry machines. As discussed above, associated with each of the laundry machines is a cleaning product dispenser capable of dispensing detergent, softener, souring agent and bleach, through three or four independent delivery systems. Particularly in view of the fact that automatic dispensers are so expensive, there is a need for a dispenser which can service more than one laundry machine. Preferred dispensers of the present invention possess this capability. Still another problem with prior art laundry machines is that very concentrated cleaning chemicals are delivered to the washing basin at various times during the washing cycles. Use of such concentrated solutions diminishes the useful lives of the components (tubes, fittings, pumps, and the like). Further, when these concentrated solutions are dumped into the washing basin, the laundry which first receives the concentrated solutions will be most affected, leading to non-uniform cleaning and, in extreme cases, permanent staining.
In view of the above, preferred embodiments of the present invention include dispensers for handling multiple products (with a single delivery system) and multiple laundry machines, and which are also capable of delivering relatively dilute cleaning solutions.